Commit 41d1d75a84e03219ec037b0f7982a67fb031eae7
2020-03-20T17:49:37
cmake: replace CheckFunctionExists with CheckSymbolExists Checking functions with `CheckFunctionExists` may get wrong results, we should replace it with `CheckSymbolExists`, which is recommended by the cmake official documentation. Before using `CheckSymbolExists`, we use `CheckIncludeFiles` to check header files and save the available header files in a variable that guarantees `CheckSymbolExists` and `CheckTypeSize` to work correctly. This approach is modeled after the cmake scripts of `curl`. The following functions or files were not found before modification, they can now be found: - msys2 + mingw-8.1.0 on Windows10 or mingw-7.3.0 on Ubuntu-18.04 timerclear timercmp timerisset - windows10 getaddrinfo getnameinfo getprotobynumber getservbyname putenv strtoll timerclear timercmp timerisset - ubuntu-18.04 sys/sysctl.h timeradd timerclear timercmp timerisset - MacOS 10.13 sys/random.h timeradd timerclear timercmp timerisset